This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are exploring the profound roles of ion fluxes during two vertebrate developmental stages: the establishment and patterning of the left-right (LR) axis during early embryogenesis, and the regeneration of skin, muscle, skeleton, and spinal cord during regeneration of an amputated appendage. (See SPID 0104) Both of these processes are fascinating as questions, and critically important for guiding the design of biomedical approaches to, in the case of LR patterning, correct birth defects (such as Hypoplastic Left Heart Syndrome, heterotaxy, asplenia, polysplenia, transposition of the major blood vessels, situs inversus, etc.) which together affect more than 1 in 8000 births, and in the case of regeneration, to replace diseased or damaged tissue by harnessing the body's latent ability to recreate tissue.